Loud-speaker driving motor



July 30, 1929. I. s. BOBROVSKY 1,722,335

LOUD SPEAKER DRIVING MOTOR Filed June 29, 1927 INVENTOR IGOR S- BDBROVSKY Patented July 30, 1929.

UNITED STATES PATENT OFFICE,

IGOR S. BOIBROVSKY OF ROCHESTER, NEW YORK, .AB8IGINOB, BY HESKE ASSIGNMENTS, 1'0 UNITED .BEPBODUCERB CORPORATION, A CORPORATION OF NEW JERSEY.

LOUD-HPEAKEB DRIVING MOTOR.

Application filed June 29,

This invention relates to telephonic apparatus, and more particularly to a driving unit or motor especially useful in loud speakers desired to reproduce the entire acoustic range with a high quality of reproduction and operating in response to currents of audio fre quency to drive or vibrate a diaphragm, and more particularly to drive a relatively small diaphragm with relatively large amplitudes of motion.

It is an object of this invention to provide apparatus of the class described, in which the necessary expense for tools, parts, and materials is minimized and in which the labor necessary to assemble the device is likewise minimized, without sacrificing quality of workmanship or material, in order to produce a high quality driving unit at a minimum expense.

It is a further object of this invention to provide a driving unit which may be easily and quickly assembled or disassembled for p the purposes of inspection or adjustment, and

one which is relatively open so that inspection of adjustments can be made with the unit in its assembled form. It is a further object of this invention to. provide a simplified construction such that all the movable parts may be assembled in operative relation including the diaphragm supporting and driving mechanism in their pro er operating positions, after which such mec anisrn maybe mounted upon a permanent magnet without interfering in any Way with any of the adjustments already made. Still'other objects'and advantages of m invention will be apparent from the specification.

The features of novelty which l believe to be characteristic of my invention are set forth with particularity in the appended claims. y invention itself, however, both as to its fundamental rinciples and as to its particular embodiments will best be understood by reference to the specification and accompanying drawing, in which:

Figures 1 and 2 are respectively side and front elevations of the completed driving unit,

Figure 3 is a sectional view on lines 3-3 of Figure 2,

Figure l is a sectional view on lines l-4 of Figure 1,

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mar. Serial H0. 202,213.

Figure 5 is a perspective view of the nonmagnetic saddle,

Figure 6 is a perspective view of the ratio arm and Figure 7 is a detail sectional view on lines 7? of'l igure 1.

In accordance with my invention, 1 provide a saddle or carrier of non-magnetic material, and preferably in the form of a stamping having an intermediate portion cut out I to and a connection made between said armature and said ratio arm for the purpose of providing a relatively large amplitude of motion of the diaphragm drivin rod from the relatively small motions whic are practical for the armature.

All moving parts and all parts requiring adjustment including the diaphragm, if ClGSllfBd may he placed in position and adjusted and fastened securely with respect to the said saddle or carrier, after which the carrier and its associated mechanism may be mounted as a single entity upon the permanent magnet adording the necessary magnetizin force.

Referring now more particular y to Figures 1 and 2,1 designates a suitable permanent magnet having p0 es 2 and 3 of opposite mag netic polarity and d designates generically a carrier or saddle of non-magnetic material preferably a stain ing of brass having portions 5 and ti exten ing outwardl on opposite sides of a median plane; said saddle comprises a pair of oke members at opposite sides connecting tlie outwardly projecting portions 5 and 6. The yoke portion referably com prises a pair of spaced para el flat portions 7 and 8 on one ei is and connecting the portions 5 and 6 said po tions 7 and 8 hemg connected by a web 9. As 'milar pair of spaced portions 10 and 11 are p ovided at the opposite side from the member .s 7 and 8, connected similarly by a top web 12. The portions 5 is prefera 1y made longer than the portion 6 to permit of the outer end being turned downwardly to provide a flange 13 to which a ratio arm may be secured as will be hereafter described.

A portion of the material of the saddle 4 is cut away at 14 to provide for mounting of an armature extending parallel to the portions 7 and 8, and 11, and a rectangular slot having side walls 15 and 16 is also formed by cutting away part of the material to provide a guide for receiving and positioning the armature carrying spring 18. The material of the carrier or saddle ispreferably upset intermediate the ends of the slot 15 as at 17 in such manner that the edges 15 and 16 project upwardly above the spring 18 when in position, and serve as lateral guides therefor. It is to be noted that the entire. saddle or carrier is preferably stamped from non-magnetic material such as brass, whereby the expense of diecasting a number of cooperating parts to be later assembled, is avoided.

An armature 25 of magnetic material of preferably rectangular cross-section is provided passing through the spring 18 and extending on opposite sides thereof. The armature 25 is secured in position in an opening in the spring b means of soldering, welding or the like, an is arranged to vibrate in the plane defined by the poles of the magnet, as shown in Figure 4, about the center of the spring as an axis. A pair of actuating windings 26 and 27 preferably in the form of spools are provided, which are mounted on opposite sides of the spring 18 around the armature and connected to the source of currents which it is desired to convert into sound.

In order to assemble the apparatus thus far described, the armature is mounted within the spring and securely fastened in position, after which the spring. is laced in position between edges 15 and 16- an fastened to the saddle by means of bolts 19 and passing through its extremities and enga ing portions 6 and 5 respectively of the sa die: the coils are then placed in position.

The ratioarm vided having the end portion 29 adapted to be bolted to the downwardly extendin portion 13 of the saddle 4 and having a fi exible bent portion 30 and a rigid portion 31 extending normally to the !portion 29, and preferab y rovided for sti ening purposes with an angularly extending flan e 32. The end of the arm 31 may be provided with a notch 33 adapted to receive a threaded driving rod 34 connected to on 35, to which the cone 36 is secured as by she acking or the like. The head of the driving rod 34 ma be secured in the notch 33 by soldering or t e like. A driving connection 37 is provided between the lower and of armature and a suitable point on the straight portion 31 of ratio arm 28. The exact location of this point of connection on 28 see Figure 6)'is proarm 31 will be varied in accordance with the ratio of movement of the armature and that of the center of the diaphragm. In the case of a cone of about seven inches outside diameter the point will be chosen about two-thirds of the way from the bend to the notch 33, thereby multiplying the motion of the armature by 3/2 before applying it to the diaphragm driving rod 34.

A plurality of pole pieces 41 and 42 which may comprise a series of laminations, are passed between the spaced arms 7 and 8 on the one side and spaced arms 10 and 11 on the other side and secured in position by suitable bolts 43 and 44 to the spaced arms 7 and, 8 on the one side and by bolts 45 and 46 to the spaced arms 10 and 11 on the other side.

The inwardly projecting ends of the pole pieces 41 and 42 are preferably cut away to define the inwardly projecting ends 50 and 51 of the pole piece 41, and 52 and 53 of the pole piece 42, the cut away portions of the pole pieces defining a coil receiving space in which are positioned windings 26 and 27.

It may be desired to cut oil the outer laminations of the pole pieces 41 and 42 at such point that it is not necessary to cut away any portion of such laminations in order to provide a coil receiving space, but the inner laminations corresponding to the thickness of the armature are so cut away to permit of adjusting the pole pieces with respect to the armature to provide a relatively small air gap. Suflicient clearance will be provided in the holes in the pole pieces for the bolts 43 44, 45 and 46, to permit of adjustment 0 these pole pieces within the spaced portions 7 8, 10 and 11, so that the pole pieces may 7 be properly adjusted and secured 1n adjusted position by the clampingof said bolts.

It is to be noted that when the assembly thus far described has been completed, all moving parts are secured in their desired adjusted position, and in articular, the pole pieces and armature are a justed for operation: the cone 36 may or may not be connected to the driving rod 34 at this point, but in any event, the connection of the cone will notdisturb the adjustment and operating position of the armature with respect to the pole pieces, for

the reason that the driving rod 34 is made sufficiently strong to carry and support the weight of the cone, and the connection to the ratio arm 28 is such that the entire weight of the cone and driving rod is carried by the said arm and does not react upon the armature. All that remains to be done to complete the unit is to bolt the pole pieces 41 and 42 to the ends of the magnet poles 2 and 3 by means of bolts 47 and 48, after the cooperating faces of the magnet poles and the 'pole pieces have been ground to provide for a smooth fit. The driving apparatus is now complete and if the cone has not already been secured to it, this may nowbe done by means araaeae of nuts 55 and 56 positioned on opposite sides of the cup 35, after which the entire device may be mounted u on a suitable base and placed within a cabinet.

While the apparatus according to my invention is particularly adapted to drive a cone arranged as described, it is not limited thereto, but is adapted to drive any diaphragm, and particularly adapted to drive a free edge diaphragm in which the weight of the cone is carried and the cone entirely su ported by the driving mechanism.

t is also to be noted that in its complete and operating form, all moving parts and particularly the adjustment between the pole pieces and armature, are open to inspection without disassembling any part ofthe apparatus, so that if for any reason the ad]ustment becomes disturbed, it is a simple matter to inspect the device to ascertain the trouble and remedy it.

While I have shown and described certain preferred embodiments of m will be understood that mo ifications and changes may be made without departing from the spirit and scope of my invention, as will be understood by those skilled in the art.

][ claim a 1. Telephonic apparatus comprising a magnet having poles of opposite polarity, a saddle member of non-magnetic material, an armature carried by said saddle, and adapted to be vibrated at audible frequencies, a ratio arm having one end secured to said saddle and the other end free to vibrate, a diaphragm connected to said ratio arm, and a connection from said armature to said ratio arm at a point intermediate the connection of said diaphragm thereto and the fixed end thereof.

2. Telephonic apparatus comprising a magnet having poles of opposite polarity, a saddle member of non-magnetic material, a flat spring carried by said saddle, an arma ture secured to said spring, and adapted to be vibrated at audible frequencies, a ratio arm having one end secured to said saddle and the other end free to vibrate, a diaphragm connected to said ratio arm, and a connection from said armature to said ratio arm at a point intermediate the connection of. said diaphragm thereto and the fixed end thereof.

3. Telephonic apparatus comprising a magnet having poles of opposite polarity, a saddle member comprising a stamping of non-magnetic material, an armature carried by said saddle and adapted to be vibrated at audible frequencies, a ratio arm having one end secured to said saddle and the other end free to vibrate, a diaphragm connected to said ratio arm, and a connection from said armature to said ratio arm at a point intermediate the connection of said diaphragm thereto and the fixed end thereof.

. e. Telephonic apparatus comprising a magnet having poles of opposite polarity,

invention, it

pole pieces of magnetic material secured thereto and extending toward each other, a saddle member of non-magnetic material having portions extending on either side of said 100 e pieces, an armature carried by said saddle and adapted to be vibrated at audible frequencies, a ratio arm having one end secured to said saddle and the other end free to vibrate, a diaphragm secured to said ratio arm, and a connection from said armature to said ratio arm at a point intermediate the connection of said diaphragm thereto and the free end thereof.

5. Telephonic apparatus comprising a magnet havin poles of opposite polarity, pole pieces of magnetic material secured thereto and extending toward each other in the plane of saidmagnet, a stamped saddle of non-magnetic material secured to said pole pieces and having portions extending outwardly on opposite sides of said pole pieces,

a spring secured to said saddle, an armature carried thereby and adapted to be vibrated at audible frequencies, a ratio arm having one end secured to said saddle and the other end free to vibrate, a diaphragm connected to said ratio arm, and a connection from said. armature to said ratio arm at a point intermediate the connection of said diaphragm thereto and the fixed end thereof.

6. Telephonic apparatus comprising a U shaped magnet having poles of opposite polarity, pole pieces of magnetic material secured thereto and extending toward each other in the plane of said magnet, a stamped saddle of non-magnetic material having a central yoke portion arranged to embrace opposite sides of said pole pieces, a' spring disposed normally to said pole pieces and secured to said saddle, an armature carried thereby and adapted to be vibrated at audible frequencies, a ratio arm having one and secured to said saddle and the other end free to vibrate, a diaphragm connected to said ratio arm, and a connection from said armature to said ratio arm at a point intermediate the connection of said diaphragm thereto, and the fixed end thereof.

7. Driving mechanism for telephonic apparatus comprising a saddle having an intermediate portion and portions extending outwardly on opposite sides thereof, said intermediate portion being formed to receive an actuating winding, a flat spring passing through said intermediate portion and secured at its extremities to said outwardly extending portions, an armature mounted on said spring for vibration at audible frequencies, a ratio arm mounted on one of said outwardly extendin portions in a manner to support and drive a ree edge diaphragm, and a connection between said armature and said ratio arm,

8. Driving mechanism for telephonic apparatus comprising a stamped saddle mom ber of non-magnetic material having an intermediate portion adapted to receive a pair of oppositely polarized pole pieces, and having portions extendin outwardly on opposite sides thereof, sai intermediate portion being formed to receive an actuating winding, a flat spring passing through said intermediate portion and secured at its extremities to said outwardly extending portions, an armature mounted on said spring for vibration in the plane of said pole pieces, a ratio arm mounted on one of said outwardly extending portions in a manner to support and drive a free edge diaphragm, and a connection between said armature and said ratio arm.

9. Driving mechanism for telephonic apparatus comprising a stamped saddle member of non-magnetic material having an intermediate portion adapted to receive a pair of oppositely polarized pole pieces, and having portions extending outwardly on opposite sides thereof, said intermediate portion being cut away to receive an actuating winding, and said intermediate portion being formed to provide a centering seat for a flat spring, a fiat spring disposed in said seat and having its extremities secured. to said outwardly extending portions, an armature mounted on said spring for vibration in the plane of said pole pieces, a ratio arm mounted on one of said outwardly extending portions in a manner to support and drive a free edge diaphragm, and a connection between said armature and said ratio arm.

10. Driving mechanism for telephonic apparatus comprising a stamped saddle memer of non-magnetic material having a pair of spaced parallel members disposed on opposite sides of an axis of symmetry, and adapted to be secured to a pair of pole pieces extending toward each other, said spaced members being connected by an intermediate portion having extensions projecting outwardly on opposite sides of said spaced members and in a plane normal thereto, said intermediate portion being cut away to re--- said armature, a ratio arm mounted on one of said extensions for supporting and driving a free edge diaphragm, and a connection between said armature and said ratio arm.

11. Driving mechanism for telephonic apparatus comprising a carrier of non-magnetic material, pole pieces secured to said carrier, an armature resiliently mounted on said carrier for vibration at audible frequencies, an actuating winding for said armature mounted on said carrier, a ratio arm having one end secured to said carrier, a diaphragm adapted to be supported and driven by said ratio arm, and a connection between said armature and said ratio arm.

12. A loud s eaker comprising a magnet having poles 0t opposite polarity, a carrier of non-magnetic material, pole pieces secured to said carrier, an armature resilientl mounted on said carrier for vibration at audlble frequencies, an actuating winding for said armature mounted on said carrier, a ratio arm having one end secured to said carrier, a light conical diaphragm having a diameter of seven inches, a driving connection between said ratio arm and said diaphragm, and a connection between said armature and said ratio arm so arranged as to cause said driving rod to have an amplitude of motion of three halves times the amplitude of motion of said armature.

Signed at Rochester, in the county of Monroe and State of New York, this 27th day of June, A. D. 1927.

IGOR s. BoBRovsKY. 

